This invention relates to three-dimensional structures of interlocked strands and more particularly it relates to such structures in composite material.
Fiber-reinforced plastic structures have been used for many years with increasing success because of their high strength, light weight and ease of fabrication compared to the wood or metal structures which they replace. Fibers such as glass, carbon, ceramic and aramid are popular as reinforcement, and thermosetting as well as thermoplastic resins are common polymeric matrices.
Braiding with axial yarns is one process for producing such structures and generally comprises forming an array of axial yarns extending substantially parallel to the axis of the structure and interlacing braiding yarns in a pattern through the array so they are interlaced with one another and with the axial yarns. Known braiding patterns does not provide the control of the yarns necessary to locate them at particular locations in the structure so that such locations can have the characteristics of a particular yarn. This control is not possible with known braiding processes because they have strands that move throughout the process.